The back squat is a very important compound exercise which incorporates much of the large muscles of the lower limb and hip. When executed to the appropriate levels its use can have a large hormonal impact which will help to increase lean muscle mass.
It's use has good carry over into improving jump height and explosive power, and when used appropriately is a key fundemental exercise for hypertrophy, and body recomposition programs.
Elbows under the bar
Bend the bar over your shoulders
Sit into a chair
Zip up your abdominals
Screw your feet into the ground
Stand up tall
Target muscles trained
Quadriceps (mainly vastus medialis, vastus lateralis & vastus imedius)
Key movements trained
Hip extension, Knee extension, ankle plantarflexion
Best foot position for you is greatly affected by your hip joint shape
Ability to remain upright through range is affected by the length of your femur, ankle dorsiflexion range, length of your torso
Knees can go in front of toes, in fact they are required to for you to get a decent depth
Build weight upon good technique, make sure you have the form well versed at the weight you're working at before putting more weight on the bar